1. Field of the Invention
This invention relates broadly to electrically-powered fluid pumps. More particularly, this invention relates to an electrically-powered fluid pump contained in a spray head which is retrofittable onto existing pump spray containers.
2. State of the Art
Many household and industrial products are sold in containers that include a sprayer. These products include cleansers, insecticides, polishes, waxes, etc. There are several kinds of sprayers used with these products. Perhaps the most common is the push button or trigger operated pump which is seen most frequently on liquid cleansers. It has the advantage of being environmentally friendly but the disadvantage of delivering fluid in a series of pulses rather than in a continuous spray.
Another well known sprayer is the aerosol can which is sealed and charged with a gas propellant. This sprayer has the advantage that it dispenses fluid in a continuous spray, but has several disadvantages. One disadvantage is that the can cannot be refilled. Another disadvantage is that, depending on the gas used to charge the container, it can be environmentally unfriendly. Moreover, environmentally friendly propellants do not charge as well as the unfriendly gases.
Still another popular sprayer is the air pump sprayer seen most frequently with insecticides and liquid garden products. The pump sprayer includes a hand operated air pump which is used to charge the container with compressed air. After it is charged, it operates much like an aerosol can. The pump sprayer is environmentally friendly but requires a lot of effort to keep it charged because air is not as efficient a propellant as environmentally unfriendly gases such as FREON or hydrocarbon gasses.
In recent years there has been some experimentation with electrically powered pump sprayers. Most of these devices include a spray mechanism which is similar to the ubiquitous push button (or trigger) pump sprayer but which is coupled to a battery powered electric motor by a linkage which converts the rotary action of the motor to an oscillatory motion to drive the pump piston. Many of these battery operated pump sprayers are designed to work only with a specially constructed bottle, i.e. they are not retrofittable to existing pump spray bottles. They also are heavy, expensive, and have poor power consumption (and reduced battery life) due to the weight and cost of the electric motor. Many of these battery powered pumps also have large priming volumes, thus causing a delay between the time the pump is activated and the time liquid begins to be dispensed. Significantly, these pumps do not really provide a constant spray. They provide a continuous pulsed spray like that obtained by repeatedly squeezing the trigger of pushing the button on a hand operated spray pump.